油纸复合介质中水分子扩散行为的分子动力学模拟  

Molecular Dynamics Simulation of the Diffusion Behavior of Water Molecules in Oil and Cellulose Composite Media

作　　者：廖瑞金[1] 朱孟兆[1] 周欣[1] 杨丽君[1] 严家明[1] 孙才新[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400044

出　　处：《物理化学学报》2011年第4期815-824,共10页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展规划项目(973)(2009CB724505-1);国家自然科学基金(5107736);中央高校基本科研业务费(CDJXS11152235)资助~~

摘　　要：对不同温度下水分子在油纸复合介质中的扩散行为进行了分子动力学模拟研究.通过分析水分子与纤维素形成的氢键发现,油中的水分子在模拟过程中会逐渐扩散到纤维素内并与之形成氢键,而纤维素内的水分子则与纤维素形成氢键后被束缚于纤维素中.通过分析水分子的扩散系数发现,由于油和纤维素的极性不同,使得水分子在油和纤维素两种单介质中的扩散行为有较大差别,而在复合介质中的扩散系数受水分子在油和纤维素中的比例影响较大,两者表现出很强的相关性.水分子和两介质的相互作用与两介质的极性也存在很大的关系,且不同温度下水分子与两介质的相互作用能和水分子在油和纤维素中的比例也表现出了较强的相关性.不同温度下水分子的不同分布弱化了温度对扩散系数的影响.The diffusion behaviors of water molecules in oil-cellulose composite media were studied at different temperatures using a molecular dynamics simulation. By analyzing the formation of hydrogen bonds between the water molecules and cellulose we found that the water molecules that were initially present in the oil gradually spread to the cellulose, and hydrogen bonds were formed between them. The water molecules that were present in the cellulose initially also formed hydrogen bonds and were bound to cellulose molecules. By analyzing the diffusion coefficients of the water molecules at different temperatures we found that the diffusion behaviors of the water molecules in the two single-media, namely oil and cellulose, were very different because of their different polarities. The diffusion coefficients of the water molecules in the composite media were influenced greatly by the ratio of water molecules present in the oil and cellulose and a strong correlation was apparent between them. The water molecule-oil interaction energy and the water molecule-cellulose interaction energy were also strongly related to the polarities of the oil and the cellulose. The interaction energies also exhibited a strong correlation to the distribution of water molecules at different temperatures. This was the reason for the weakened influence of temperature on the diffusion coefficient of the water molecules, which was due to the different distributions of water molecules at different temperatures.

关 键 词：分子动力学 复合介质 氢键 扩散系数 相互作用能 相关性 

分 类 号：O645.11[理学—物理化学]